1. Macromolecules
Protein

2. Proteins
Probably the most diverse group of macromolecules is the proteins.

3. Proteins
Proteins are complex polymers composed of C, H, O and N.
Polymer : large molecule formed when many smaller molecules bond together

4. Functions of Proteins
Serve as structural components of animals, build and repair body tissue.
Maintain cell growth
Serve as control molecules (enzymes)
Serve as transport and messenger molecules
Provide as energy if sufficient carbohydrates and fats are not supplied by the diet.
Ex. Keratin, elastin, collagen

5. Proteins
The building blocks of proteins are smaller molecules called amino acids held together by peptide bonds
Most end in “ine”
Despite the wide variety of life on Earth, all living organisms use only 20 different amino acids to produce the proteins they require

6. Proteins
Green plants can make all 20 essential amino acids on their own; animals cannot.
Thus, animals, including humans, must get some of these essential amino acids from the foods they eat.

7. All animal proteins are complete proteins: i. e
All animal proteins are complete proteins: i.e. milk, eggs, cheese, fish and meat have all 9 amino acids.
Proteins from some plant sources, such as brewer's yeast, certain nuts, soybeans (tofu is made from soybeans), cottonseed, and the germ of grains are also complete proteins.
Partially complete proteins do not contain all 9 of the essential amino acids but a limited amount of one or more of them. Partially complete amino acids provide normal maintenance but will not support growth.

8. Enzymes are important proteins found in living things.
An enzyme changes the rate of a chemical reaction.
Enzymes are involved in nearly all metabolic reactions
Usually end in “ase”
Proteins

9. Proteins Substrate- Component in an enzyme reaction
Enzyme reactions take place in the active site
Substrate + Enzyme Product + Enzyme
The enzyme is unchanged in the reaction.

10. Proteins
Each enzyme is specific to only one reaction.
This reaction is often compared to a lock and key.